Process for preventing the staining of polyamide fibre material treated with fluorescent whiteners

ABSTRACT

Polyamide fibre material treated with fluorescent whiteners (also known as optical brighteners) is prevented from being stained by applying to the fibre material either simultaneously with the fluorescent whitener or in the form of an aftertreatment of the whitened fibre material, an emulsion containing a watersoluble fixing agent with affinity to fibres, an organic solvent or solvent mixture and at most 10 % of water, relative to the preparation, and optionally an organo-soluble dispersing agent. The process is carried out at 20* to 120*C according to the exhaustion method. The finish renders the fibrous material resistant to staining and soiling.

Elnited States Patent [191 Mueller et al.

[ Nov. 19, 1974 Hans-Ulrich Berendt, Allschwil; Melvin Harris,Arlesheim, all of Switzerland [73] Assignee: Ciba-Geigy AG, Basel,Switzerland [22] Filed: May 30, 1972 [21] Appl. No.: 257,722

[30] Foreign Application Priority Data June 7, 1971 Switzerland 8274/71[52] U.S. Cl. 117/335 T, 117/1388 N, 8/1 W, 8/74, 8/84, 8/156, 28/75[51] Int. Cl D06m 3/40 [58] Field of Search 1l7/33.5 T, 138.8 N; 28/75;8/74, 156, 1 W, 84

[5 6] References Cited UNITED STATES PATENTS 3,182,059 5/1965 Konishi eta1. 117/335 T 3,265,461 8/1966 Luetzel et a1. 8/1 W 3,290,111 12/1966Hees et a1. 8/74 3,371,089 2/1968 Gold et al. 117/335 T 3,485,76112/1969 Haxby et al. 117/335 T 3,490,860 l/l970 Soiron et a1. 8/743,642,783 2/1972 Siegrist et a1. 8/1 W 3,682,900 8/1972 Liechti et al.117/335 T FOREIGN PATENTS OR APPLICATIONS 3,710 l 964 Switzerland 7,7960/ 1 964 Switzerland 12,362 0/ 1 964 Switzerland 432,485 O/1962Switzerland 1,535,352 0/1968 France 715,919 0/1954 Great Britain 929,0536/1963 Great Britain 8/178 Primary Examiner-William D. Martin AssistantExaminerWilliam R. Trenor Attorney, Agent, or Firm.loseph G. Kolodny;Edward McC. Roberts; Prabodh l. Almaula 7 ABSTRACT Polyamide fibrematerial treated with fluorescent whiteners (also known as opticalbrighteners) is prevented from being stained by applying to the fibrematerial either simultaneously with the fluorescent whitener or in theform of an aftertreatment of the whitened fibre material, an emulsioncontaining a watersoluble fixing agent with affinity to fibres, anorganic solvent or solvent mixture and at most of water, relative to thepreparation, and optionally an organosoluble dispersing agent. Theprocess is carried out at to 120C according to the exhaustion method.The finish renders the fibrous material resistant to staining andsoiling.

13 Claims, No Drawings PROCESS FOR PREVENTING THE STAINING OF POLYAMIDEFIBRE MATERIAL TREATED WITH FLUORESCENT WHITENERS The present inventionrelates to a process for preventing the staining of fibre materialtreated with fiuoroescent whiteners (also known as optical brightners),in particular polyamide fibre material. The process consists in applyingto the fibre material, either simultaneously with the fluorescentwhitener or in the form of an aftertreatment of the whitened fibrematerial, at temperatures of 20 to 120C, preparations which contain awater-soluble fixing agent with affinity to fibres, an organic solventor solvent mixture and at most percent water, relative to the liquor,and optionally an organo-soluble dispersing agent.

By staining is meant hereinafter the undesirable transfer of dyestuffsfrom one dyed substrate to another substrate which is dyed in adifferent shade, but in particular is white. The substrates arepreferably textile fibre materials. A

These preparations are manufactured, for example, by stirring the fixingagent with the dispersing agent to form a paste and subsequentlydiluting the paste with an organic solvent to the desired volume; beforeor after the addition of the organic solvent, water may optionally beadded. However, it has proved very suitable to dissolve the fixing agentin a small amount of water and then to correspondingly dilute thissolution by adding a solution of the dispersing agent in the organicsolvent. Fixing agent dispersions in organic solvents which are stableand do not demulsify are thereby obtained. Instead of water, it is alsopossible to use a hydrophilic solvent which is readily miscible withwater.

Suitable solvents for the process according to the invention are, forexample, solvents which are immiscible with water or are miscible onlyto a limited extent, such as the petroleum hydrocarbons, e.g., petroleumether, benzene and halogenated benzenes or benzenes which aresubstituted by lower molecular alkyl groups, for example toluene,xylene, ethyl benzene, cumene, monoand dichlorobenzene; alicycliccompounds, for example tetralin and cyclohexane, cyclohexanol;preferably, however, halogenated hydrocarbons, e.g. the solvents used inthe dry cleaning industry, trichloroethylene and perchloroethylene;furthermore, chloroform, ethylene chloride, carbon tetrachloride,dibromoethylene and the chlorinated ethanes, such as 1,1-dichloroethane,1,2-dichloroethane, l,l,l-trichloroethane and 1,1,l,2-tetrachloroethane. A further group consists of the solvents which aremiscible with water, for example the aliphatic alcohols methanol,ethanol or the propanols; ketones, such as acetone, methyl ethyl ketone,cyclohexanone; ethers and acetates, such as diisopropyl ether, diphenyloxide, dioxan, tetrahydrofuran; glycol derivatives, such as ethyleneglycol monomethyl, monoethyl and monobutyl ether and diethylene glycolmonomethyl or monoethyl ether, also pyridine, acetonitrile, diacetonealcohol, ethylene carbonate, y-butyrolactone, N,N-dimethyl formamide,N,N-dimethyl acetamide, N-methylpyrrolidone, tetramethyl urea,tetramethylene sulphone, dimethyl sulphoxide etc.

It is also possible to use mixtures of the cited solvents.

The fixing agents having affinity to the fibres and which are applied tothe fibre material to prevent staining by means of the actualfluorescent whitening process, but may also be present in the treatmentbath together with the fluorescent whitener and then simultaneouslybecome attached to the substrate, are as a rule anionic water-solublecompounds. They should not have any natural colour, or at least theyshould have no colour cast on the fibre substrate.

Particularly suitable fixing agents are the watersoluble anionicpolycondensation products of diaryl sulphones having at least onephenolic hydroxyl group with formaldehyde. Suitable aromatic componentsare bicyclic, but are chiefly monocyclic compounds which have at leastone phenolic hydroxyl group. Preferred substituents which may be presentin the aromatic compounds are sulphonic acid groups, halogen atoms oralkyl radicals, in particular those with l to 4 carbon atoms. As suchcompounds there may be used: phenol, monoor dialkyl, phenols, e.g.cresols or xylenols, monoor diahalophenols, e.g. chlorophenols ordichlorophenols, resorcinol or pyrocatechol.

The sulphones are manufactured from the above described phenoliccompounds by known methods, for example by reaction with sulphuric acidat elevated temperature. In so doing, it is also possible to usemixtures of the described aromatic components.

These sulphones undergo polycondensation with formaldehyde, the processbeing carried out by methods known in the art, for example in an acid oralkaline medium at elevated temperature. However, the condensation neednot be carried out exclusively with sulphones, but also with mixtures ofsulphones and sulphonic acids of the described phenolic compounds oralso together with aromatic compounds which are free from hydroxylgroups, such as naphthalene or substitued naphthalane, e.g., the mono-,dior trisulphonic acids of naphthalene, preferablynaphthalene-Z-sulphonic acid, or l,2,3,4-tetrahydronaphthalenesulphonicacids. In this case, the polycondensation product should contain atleast 30, but preferably 40 molar percent of sulphone. On the otherhand, if solely sulphones undergo polycondensation, they are sulphonatedeither before the condensation or else the polycondensates aresulphonated. In this connection, it is also possible to introducesulphonic acid groups both before and after the condensation withformaldehyde. Condensation products of aromatic sulphonic acids whichare free from hydroxyl groups with formaldehyde are likewise suitable.Mention may also be made of those condensation products which, insteadof the S0 group, contain in the diaryl sulphones described hereinbeforea sulphur atom (diarylsulphide type), an oxygen atom (diphenyl ethertype), a methylene(CI-I or substituted methylene group or a keto group(-C'==O).

As dispersing agents for the manufacture of the dispersed fixing agentpreparations it is advantageous to use anionic or non-ionicsurface-active compounds, with care being taken that these have a goodsolubility in the organic solvents used. The solubility of thedispersing agents must not be less than 0.5 g/l.

Suitable representatives of such surface-active compounds are thosewhich are obtained, e.g., by addition of ethylene oxide to long chainamines and alcohols, phenols or fatty acids containing from 12 to 22carbon atoms. They belong to following types of compund:

a. ethers of polyhydroxy compounds, such as polyoxalkylated fattyalcohols, polyoxalkylated polyols, polyoxalkylated mercaptans andaliphiatic amines, polyalkylated alkylphenols and -naphthols,polyoxalkylated alkylarylmercaptans and alkylarylamines; also thecorresponding esters of these compounds with polybasic acids, such assulphuric or phosphoric acid, optionally also in the form of ammonium oramine salts;

b. fatty acid esters of ethylene and polyethylene glycols and ofpropylene and butylene glycol, of glycerol and of polyglycerols andpentaerythritol, also of sugar alcohols, for example sorbitol;

c. N-hydroxyalkyl-carbonamides, polyoxalkylated carboxylic amides andsulphonic amides.

As examples of dispersing agents from these groups which can be usedwith advantage there may be cited: the monoethanolamine salt of thephosphoric acid ester of the addition product of oleyl alcohol and 6moles of ethylene oxide; the ammonium salt of the acid sulphuric acidester of the addition product of 17 moles ester of the addition productof 5 moles of ethylene oxide with Z-ethyl-hexanol.

Also suitable are mixtures of the above cited surfaceactive compounds.

amide group.

The fluorescent whitening agents which can be used at ullso be presentin the form of a salt, or a sulphonic acid Suitable fluorescentwhitening agents which contain at least ons sulphonic acid group, acarboxylic acid group or an amide group, are derived from the follow- 15ing basic types:

a. acids of the formula R1 R1 @co-nn emcaQxu-W-Q R2 so 3H H 5 R2 ofethylene oxide and oleyl alcohol; the addition product of 4 moles ofethylene oxide with nonylphenol; the addition product of 8 moles ofethylene oxide with 1 mole of p-tert.octylphenol; the addition productof 9 4,4-bis-(acylamino)-stilbene-2,2'-disulphonic sents -NH-CO-CH or-OCl-l acids of the formula moles of ethylene oxide with nonylphenol;the addition product of 8 moles of ethylene oxide with cetyl or oleylalcohol; the reaction product of coconut fatty acid and 2 moles ofdiethanolamine; of or 6 moles of ethylene azolyl-Q CH cuoxide withcastor oil, of moles of ethylenes oxide NQN ' 4 moles ofcthylenc oxidewith l mole of oleic acid sorbitan ester and sorbitan-monolaurate.-monopalmitate and -monostearate, the sodium salt ofdodecylbcnzenesulphonic acid. the sodium salt of the phosphoric acidwherein R, and R represents, e.g., aloweralkoxy, al-

kylamino, alkylolamino or anilino group.

c. 4,4'-bis-(azolyl)-stilbene-2,2'-disulphonic acids 40 the formula azolyl SO H H0 8 iii/herein the following groups may represent azolyl:

d. stilbyl-naphthotriazoles of the formula n N Q-Cl-LCI N R1 SO3HH,h'a1ogeno wherein the following substituents may represent R {N SO3H,'"SO NHCzHs, "SO2NH(CH2)3,

5 6 e. bis-(benzoxazol-Z-yl)-derivatives of the general wherein R,represents, e.g., a hydrogen atom, an alkyl formula or aryl group, Rrepresents a hydrogen atom or a chlo- O O rine atom and R represents asulphonic acid, sulphong amide, carboxylic acid or carboxylic acid estergroup.

W R R l a it L N l a 5 wherein R represents bis-styrylaryl compounds ofthe formula i. Styrylbenzoxazoles of the formula in which X =NH, S, O,and R may represent, or bis-benzoxazolylaryls of the formula c Ar c (sox) N N m e.g., a hydrogen atom, a lower alkyl group and sulwherein Xrepresents, e.g., -OH or NH,, and Ar is phonic or carboxylic acid group.and m is l to 4, preferably 1 and 2. In addition to the f.monomethine-cyanines of the formula cited substituents, the compoundsmay also contain CH 3 CH 3 wherein R represents, e. g., an alkyl oralkoxy group and further chromophoric substituents.

X represents an aryl or -Oalkyl group. k. Oxidiazole compounds of theformula g. 2,7-bis-(aroylamino)-dibenzothiophene dioxide- 0 l 3,6dlsulphomc acids of the formua V V D 50 QU CHGC/ C (13) l ll ll no s $0so I -c0on 5) co HN NH COQ 55 wherein B represents a phenylene, furyleneor thienyl R I R radical, A represents an aryl radical and n is l or 2.

whemin R represents eg an alkoxy p phenyl 1.Quatern1sedbenzofuranoylbenzimidazoles of the formula group.

h. 1,3-diaryl-pyrazolines of the formula 60 R nc /N 2 (11) I C 9 x (16 N3 \N l 7 8 wherein R and R represent hydrogen or together repularorganic acids containing from 1 to 4 carbon atoms, resent a condensedbenzene radical, R represent hyfor example formic or acetic acid, orammonia or suitdrogcn, methoxy or methyl, R represents hydrogen or ableamines. methyl, R represents methyl, phenyl or benzyl, R rep- Theamounts in which the fixing agent is applied varesents methyl or benzyl,R represents hydrogen, 5 ries within wide limits and in the paddingprocessis0.l methyl, methoxy, chlorine or methylsulphonyl and X to 10percent relative to the impregnating liquor, or 0.1

represents chlorine, the methylsulphonic acid radical to 10 percent,preferably 0.5 to 5 percent relative to or the p-toluenesulphonic acidradical. the fibre material in the case of the exhaust process.

The water-insolubilising substituents cited in the The amount ofdispersing agent required in each case given formulae together with thesulphonic and carbox- 1 varies correspondingly and preferably bothcompoylic acid groups have representative character and may nents areproportional to each other, i.c., as the amount be replaced orsupplemented by further substituents of fixing agent increases so alsodoes the amount of diswhich are common for the classes of the citedcompersing agent. The ratio of fixing agent to dispersing pounds. agentis advantageously between 1:100 and 1:2. Suit- It is also possible touse fluorescent whitening agents able liquor ratios are between 1:5 and1:100, preferably of different structure for the process according tothe between 1:5 and 1:20.

invention with equal success, provided that they pos- In order to finishthe fibre substrates which have been sess at least one of the citedwater-solubilising groups. treated in a single bath or have beensubjected to an af- Fluorescent whitening agents which possess twowatertertreatment, the liquor is advantageously centrifuged solubilisingsulphonic acid groups prove especially adoff and the materials are thendried in a flow of warm vantageous for the present process. i

Suitable fibre materials according to th invention The fibre ubstratestreated according to the invenare P p y synthetic polyamide fibres,-gnylon 6, tion are protected against staining when dyed or nylon 66,nylon 6,10 (from hexamethylene diamine printed parts of the same or ofanother fibre substrate and Sebaeie mmy 11 or nylon 616/6 p y arewashed, so that, e.g., in a domestic optionally of hexalhethylenediamihe adipic acid and p brightened and finished parts of a fabric arenot stained tam), and also blended fabrics which contain synthetic byrinsed out dye. It is also possible to protect the depo yam fibres- Thefibre metel'iel y be in y gree of whiteness of pure white opticallybrightened sired stage of processing. fibre substrates against staining.Suitable dyestuffs for The fixing agent is pp simuheheouslll with thedyeing synthetic polyamide fibres are preferably acid, fluorescentwhitener from organic solvent liquors by disperse, reactive d t complexdy They mefms 0f the exhaust p For the Single bath PP bebng, forexample, to the known classes of monoand cation, the treatment baths maybe advantageously predisazo dyes, also f the anthraquinoneq methine,pared for example as follows: azomethine, azostyryl and formazane dyes.These dyes,

The fluorescent whitener is made into a Paste with which are eitherwater-soluble or only dispersible in the dispersing agent, the pastediluted with the desired water, may be used Sing]y or in admixtureOptionally,

amount of an Organic solvent and F Preparation i it is also possible touse other suitable types of dye.

mixed w a Preparation of h fixmg age"t Whlch The following Examplesillustrate the invention, the (humid l" Water an Orgamc solvem' Anotherparts and percentages being by weight unless otherwise quence is alsoposslble. If an aftertreatment with the 40 Stated fixing agent follows,the treatments with fluorescent whiteners can be carried out both inorganic solvent li- EXAMPLE 1 quors and in aqueous baths, in whichlatter case it is ex- A piece of synthetic polyamide knitted materialpedient to effect an intermediate drying of the fibres.(nylon-l-lelanca-jersey) is treated at C and in a li- The finishing withthe fixing agent is always carried out 5 quor which contains in 200 mlof perchloroethylene 0.2 from an organic solvent. g of the fluorescentwhitener of the formula o N N\ n c NH CH= c N (101) l 3 I SO 1\a 2 Thetemperature ranges for the application are be- 0.1 g of the fixing agentdescribed below in 3 ml of tween 20 and 120C, preferably between 40 andwater and 2 g of the surfactant mixture described here- 80C. Thetreatment times are between about 1 and 30 inbelow.

minutes, preferably between 5 and 15 minutes, in the The bulk of theliquor is subsequently removed by case of the aftertreatment and thesimultaneous applipumping off and centrifuging and the substrate iscomcation. pletely dried by a flow of warm air and freed from the lastremaining traces of solvent. The substrates has a The pH values of thepreparations may be in the acid, good whitened appearance. Thesimultaneously apneutral or alkaline range and comprise a range fromplied fixing agent protects the white ground from being about pH 4 to 9,preferably from pH 5 to 8. stained when washed with a colored print andagainst It is possible to adjust the pH by means of the molecstaining ina domestic wash.

Manufacture of the fixing agent: to a suspension of 70 g of4,4-dihydroxydiphenylsulphone in 35 g of acetic anhydride is addeddropwise while stirring and at room temperature 35 g of cone. sulphuricacid. The temperature is then raised to 98100C and kept at this levelfor 6 hours. The 75 ml of water is added in small amounts at a pressureof 30 to 55 mm HG column. Simultaneously, 88 ml of liquid is distilledoff from the reaction mixture. The residual reaction mixture is dilutedwith a further 20 ml of water, treated with 20 g of 30 percent aqueousformaldehyde solution and heated for 5 hours to lO0l05C. The batch isthen allowed to cool and the viscous condensation product is treatedwith 30 percent sodium hydroxide solution until a pH of 7 is reached.The resulting product may be diluted with water to any desired extent.

The surfactant mixture has the following composi- Hon:

1 part of the monoethanolamine salt of the phosphoric acid ester of theadduct of oleyl alcohol and 6 moles of ethylene oxide,

2 parts of the adduct of nonylphenol and 4 moles of ethylene oxide,

2 parts of perchloroethylene and 2 parts of water.

Instead of the above mentioned fluorescent whitener, it is also possibleto use the whiteners of the following formulae:

NaO S SO Na l n- 0' (106 HCHC/ JSZNHZ ExampleZ 2 g of the fluorescentwhitener of the formula "I SO ha 03 H GQ- CH Q (104) 3 Cl liquor is thenremoved by pumping off and centrifuging and the substrate is dried by aflow of warm air.

A good white effect is obtained which is protected by the simultaneouslyapplied fixing agent from being stained if a subsequently manufactedprint is washed and against staining in a domestic wash.

The following fixing agents are also suitable:

1. The condensation product of 4,4'-dihydroxy-3,3-dimethyldiphenylsulphone, sulphuric acid and formaldehyde. Manufacture:In a suspension of 70 g of 4,4- dihydroxy-3,3-dimethyl-diphenylsulphonein 35 g of acetic anhydride is added dropwise while stirring and at roomtemperature 35 g of cone. sulphuric acid. The temperature is then raisedto 98-100C and kept at this level for 6 hours. The 75 ml of water isadded in small amounts at a pressure of 30 to 50 mm Hg column.Simultaneously 88 ml of water is distilled off from the reactionmixture. The residual reaction mixture is diluted with a further 20 mlof water, treated with 20 g of 30 percent aqueous formaldehyde solutionand heated for 5 hours to ll05C. The batch is then allowed to cool andthe viscous condensation product is treated with 30 percent sodiumhydroxide solution until a pH of 7 is reached. The resulting product maybe diluted with water to any extent desired.

2. A product with similar properties is obtained by adjusting thereaction mixture to a pH of 8 to 8.5 with 30 percent sodium hydroxidesolution before the formaldehyde is added.

3. The condensation product of a sulphone mixture(4,4-dihydroxy-diphenylsulphone, 4,2'-dihydroxydiphenylsulphone),sulphuric acid and formaldehyde.

4. The condensation product of 4,4'-dihydroxydiphenylsulphone,naphthalene, sulphuric acid and formaldehyde.

EXAMPLE 3 20 g of a polyamide fabric (nylon 6) is treated for 20 minutesat 40C with the following liquor; 0.08 g of the fluorescent whitener ofthe formula (105) together with 0.1 g is dissolved in 1.5 ml of water.To this solution is added 1.5 g of the addition product of 8 moles ofethylene oxide with p.tert.octylpheno1 in 100 m1 of1,1,l-trichloroethane. The procedure as described in Example 1 is thencarried out. The whitened finished fibre material is protected againststaining on being washed.

Fixing agent A mixture of 317 g of 4,4-dihydroxy4-methyldiphenylsulphone and 105.5 g of l-hydroxy-2-methylbenzene-4-sulphonic acid in 100 ml of water is made alkaline with463 g of 30 percent aqueous sodium hydroxide solution. Upon addition of162 g of 37 percent aqueous formaldehyde solution the reaction mixtureis stirred for 5 to 6 hours at l00-102C. The resulting condensationproduct 7 may be diluted to any desired extent with water without anyprecipitation resulting.

Instead of the above cited surfactant, it is also possible to use theaddition products of moles of ethylene oxide with oleylamine or of 4moles of ethylene oxide with oleic acid sorbitan ester.

EXAMPLE 4 50 g of a polyamide filament yarn is treated in the followingliquor for 30 minutes at 60C; 0.5 g of the fluorescent whitener of theformula (102) is diluted with 7.5 ml of water and pasted with 7.5 g ofthe addition product of 15 moles of ethylene oxide with castor oil. Thepaste is then diluted with trichloroethylene to 1.5 l. The liquor isthen centrifuged off and the white effects obtained by applying thefluorescent whitener to the yarn are protected by treating the materialfor 5 minutes at 50C with a preparation which contains 0.125 g of thefixing agent 1 according to Example 2, 10 ml of water and 8 g of theabove mentioned dispersent in 0.5 1 of benzene.

The liquor is then centrifuged off the yarn is dried in a flow of warmair. The yarn is protected against obtaining on being washed.

The fluorescent whitener may also be applied from an aqueous liquor, inwhich case an intermediate drying is appropriate before theaftertreatment.

Other suitable solvents for the aftertreatment are: trichloroethylene,toluene, dichlorobenzene, bromobenzene or pertroleum ether.

We claim:

1. A process for preventing the staining of opticallybrightenedsynthetic polyamide fiber material, which comprises the step of applyingto the fiber material at a temperature of 20 to C (a) simultaneouslywith an optical brightener in organic solvent or (b) as anafter-treatment of optically brightened fiber material, a preparationwhich contains a water-soluble fixing agent with affinity for thepolyamide fibers, an organic solvent, and 0 to 10 percent of water,wherein the fixing agent is a polycondensation product of formaldehydewith an aryl sulphonic acid or a diarylsulphone, and wherein the opticalbrightening agent contains at least one water-solubilizing agent. 7 V 7l 2. A process according to claim 1, wherein the fixing agent is appliedsimultaneously with the optical brightening agent in a solvent liquor. 7v

3. A process according to claim 1, wherein fibre material treated withan optical brightening agent in solvent liquors is subjected to anaftertreatment with the fixing agent. J

4. A process according to claim 1, wherein fibre material treated withan optical brightening agent in aqueous liquors is subjected to anaftertreatment with the fixing agent after an intermediate drying of thematerial has been effected.

5. A process according to claim 1, wherein the optical brightening agentis selected from the group consisting of monoor disulphonic acids, theiramides or carboxylic acids of 4,4-bis-(acylamino)-stilbenes, 4,4-bis-(triazinylamino)-stilbenes, 4,4 -bis-( azoyl stilbenes,stilbylnaphthotriazoles, bis-(benzoxaibl-Z- yl)-derivatives, monomethinecyanines, 2,7-bis- (aroylamino )-dibenzothiophene dioxides, 1 ,3-diarylpyrazolines, styrylbenzoxazoles, bis-styrylaryl compounds,bis-benzoxazolylarylene compounds oxidiazole compounds or quaternarybenzofuranylbenzimidazoles.

6. A process according to claim 1, wherein the preparation additionallycontains an organo-soluble dispersing agent.

7.'A process according to claim 1, wherein the fixing agent is awater-soluble anionic polycondensation product of a sulphonateddiarylsulphone with formaldehyde.

8. A process according to claim 7, wherein the fixing agent is acondensation product of formaldehyde with sulphonateddihydroxy-diphenylsulphones and naphthalenesulphonic acids.

9. A process according to claim 7, wherein the fixing agent is acondensation product of a diarylsulphone which contains at least onephenolic hydroxyl group with. ma wde 10. A process according to claim 9,wherein the diarylsulphone is a dihydroxydiphenylsulphone.

ylene.

1. A PROCESS FOR PREVENTING THE STAINING OF OPTICALLYBRIGHTENEDSYNTHETIC POLYAMIDE FIBER MATERIAL, WHICH COMPRISES THE STEP OF APPLYINGTO THE FIBER MATERIAL AT A TEMPERATURE OF 20* TO 120*C (A)SIMULTANEOUSLY WITH AN OPTICAL BRIGHTENER IN ORGANIC SOLVENT OR 8B) ASAN AFTER-TREATMENT O OPTICALLY BRIGHTENED FIBER MATERIAL, A PREPARATIONWHICH CONTAINS A WATER-SOLUBLE FIXING AGENT WITH AFFINITY FOR THEPOLYAMIDE FIBERS, AN ORGANIC SOLVENT, AND 0 TO 10 PERCENT OF WATER,WHEREIN THE FIXING AGENT IS A POLYCONDENSATION PRODUCT OF FORMALDEHYDEWITH AN ARYL SULPHONIC ACID OR A DIARYLSULPHONE, AND WHEREIN THE OPTICALBRIGHTENEING AGENT CONTAINS AT LEAST ONE WATER-SOLUBILIZING AGENT.
 2. Aprocess according to claim 1, wherein the fixing agent is appliedsimultaneously with the optical brightening agent in a solvent liquor.3. A process according to claim 1, wherein fibre material treated withan optical brightening agent in solvent liquors is subjected to anaftertreatment with the fixing agent.
 4. A process according to claim 1,wherein fibre material treated with an optical brightening agent inaqueous lIquors is subjected to an aftertreatment with the fixing agentafter an intermediate drying of the material has been effected.
 5. Aprocess according to claim 1, wherein the optical brightening agent isselected from the group consisting of mono-or disulphonic acids, theiramides or carboxylic acids of 4,4''-bis-(acylamino)-stilbenes,4,4''-bis-(triazinylamino)-stilbenes, 4,4''-bis-(azoyl)-stilbenes,stilbylnaphthotriazoles, bis-(benzoxazol-2-yl)-derivatives, monomethinecyanines, 2,7-bis-(aroylamino)-dibenzothiophene dioxides,1,3-diarylpyrazolines, styrylbenzoxazoles, bis-styrylaryl compounds,bis-benzoxazolylarylene compounds oxidiazole compounds or quaternarybenzofuranylbenzimidazoles.
 6. A process according to claim 1, whereinthe preparation additionally contains an organo-soluble dispersingagent.
 7. A process according to claim 1, wherein the fixing agent is awater-soluble anionic polycondensation product of a sulphonateddiarylsulphone with formaldehyde.
 8. A process according to claim 7,wherein the fixing agent is a condensation product of formaldehyde withsulphonated dihydroxy-diphenylsulphones and naphthalenesulphonic acids.9. A process according to claim 7, wherein the fixing agent is acondensation product of a diarylsulphone which contains at least onephenolic hydroxyl group with formaldehyde.
 10. A process according toclaim 9, wherein the diarylsulphone is a dihydroxydiphenylsulphone. 11.A process according to claim 1, wherein the organic solvent isimmiscible with water.
 12. A process according to claim 11, wherein theorganic solvent is petroleum hydrocarbons, benzene and halogenatedbenzenes or benzenes which are substitued by lower alkyl groups,alicyclic compounds or halogenated aliphatic hydrocarbons.
 13. A processaccording to claim 12, wherein the halogenated aliphatic hydrocarbonsare 1,1,1-trichloroethane, trichloroethylene or perchloroethylene.